Light emitting device, light emitting device package and lighting system including the same

ABSTRACT

A light emitting device including a second conductive type semiconductor layer; an active layer over the second conductive type semiconductor layer; a first conductive type semiconductor layer over the active layer; a second electrode in a first region under the second conductive type semiconductor layer; a current blocking layer including a metal; and a first electrode over the first conductive type semiconductor layer. Further, the first electrode has at least one portion that vertically overlaps the current blocking layer.

CROSS-REFERENCE TO A RELATED APPLICATION

This application claims priority under 35 U.S.C. §119 to Korean PatentApplication No. 10-2009-0039015, filed on May 4, 2009, which is herebyincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention relate to a light emitting device,a light emitting device package, and a lighting system including acurrent blocking layer.

2. Discussion of the Background

Light emitting devices (LEDs) are semiconductor devices configured toconvert a current into light. In addition, various LEDs including greenLEDs are being used as light sources in electronic devices such ascommunication devices. For example, nitride semiconductors have a highthermal stability and wide band gaps, and are combined with otherelements such as In and Al to form semiconductor layers for emittinggreen, blue and white light.

In addition, because it is easy to adjust wavelengths emitted fromnitride semiconductors, nitride semiconductors are used in high powerelectronic devices including LEDs. Further, a light emitting structureincludes a second conductive type semiconductor layer, an active layer,and a first conductive type semiconductor layer. In a vertical typelight emitting device, a second electrode applying power to the firstconductive type semiconductor layer is vertically disposed, andelectrons and holes injected to respective electrodes flow into theactive layer and are coupled to generate light.

The generated light is then emitted outward. However, a portion of lightis absorbed into the electrodes at both ends, or disappears in the lightemitting device, and thus is not emitted outwards. In more detail, thelight emitted under an n type electrode region is reflected by an n typeelectrode, and is absorbed into the device. The absorbed light alsogenerates heat in the light emitting device, which negatively affectsthe service life and reliability of the light emitting device.

SUMMARY OF THE INVENTION

Accordingly, one object of the present invention is to address theabove-noted and other problems.

Another object of the present invention is to provide a light emittingdevice that has a high light emitting efficiency by forming a currentblocking layer not affected by a heat treating process and a materialdiffusion of a reflective layer, a light emitting device package, and alighting system.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described herein, thepresent invention provides in one aspect a light emitting deviceincluding a second conductive type semiconductor layer; an active layerover the second conductive type semiconductor layer; a first conductivetype semiconductor layer over the active layer; a second electrode in afirst region under the second conductive type semiconductor layer; acurrent blocking layer including a metal; and a first electrode over thefirst conductive type semiconductor layer. Further, the first electrodehas at least one portion that vertically overlaps the current blockinglayer.

In another aspect, the present invention provides a light emittingdevice including a second conductive type semiconductor layer; an activelayer over the second conductive type semiconductor layer; a firstconductive type semiconductor layer over the active layer; a secondelectrode in a first region under the second conductive typesemiconductor layer; a schottky contact layer; and a first electrodeover the first conductive type semiconductor layer.

In still another aspect, the present invention provides a light emittingdevice including a second conductive type semiconductor layer; an activelayer over the second conductive type semiconductor layer; a firstconductive type semiconductor layer over the active layer; a secondelectrode including a reflective layer in a first region under thesecond conductive type semiconductor layer; a current blocking layer onthe second electrode layer and not overlapping the reflective layer; anda first electrode over the first conductive type semiconductor layer.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by illustration only, since various changes and modificationswithin the spirit and scope of the invention will become apparent tothose skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawings,which are given by illustration only, and thus are not limitative of thepresent invention, and wherein:

FIG. 1 is a cross-sectional view of a light emitting device (LED)according to an embodiment of the present invention;

FIGS. 2 to 6 are cross-sectional views illustrating a method ofmanufacturing a light emitting device according to a first embodiment ofthe present invention;

FIGS. 7 to 10 are cross-sectional views illustrating a method ofmanufacturing a light emitting device according to a second embodimentof the present invention;

FIG. 11 is a cross-sectional view of an LED package including an LEDaccording to an embodiment of the present invention;

FIG. 12 is a perspective view of a lighting unit according to anembodiment of the present invention; and

FIG. 13 is an exploded perspective view of a backlight unit according toan embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, a light emitting device, a light emitting device package,and a lighting system will be described with reference to accompanyingdrawings according to embodiments of the present invention.

In the descriptions of embodiments, when a layer (or film) is referredto as being on another layer or substrate, it can be directly on anotherlayer or substrate, or intervening layers may also be present. Further,when a layer is referred to as being ‘under’ another layer, it can bedirectly under another layer, and one or more intervening layers mayalso be present. In addition, when a layer is referred to as being‘between’ two layers, it can be the only layer between the two layers,or one or more intervening layers may also be present.

FIG. 1 is a cross-sectional view of a light emitting device (LED) 100according to an embodiment of the present invention. As shown, the lightemitting device 100 includes a second conductive type semiconductorlayer 130, an active layer 120, a first conductive type semiconductorlayer 110, an ohmic layer 142 disposed in a first region on the secondconductive type semiconductor layer 130, a reflective layer 144, acurrent blocking layer 150 disposed in a second region except for thefirst region on the second conductive type semiconductor layer 130, anda first electrode 160 disposed on the first conductive typesemiconductor layer 110.

In this embodiment, the light emitting device 100 also includes anadhesive layer 146 disposed on the reflective layer 144 and the currentblocking layer 150, a substrate 148, and a first electrode 160 on thefirst semiconductor layer 110. Further, a second electrode 140 caninclude the ohmic layer 142, the reflective layer 144, the adhesivelayer 146, and the substrate 148. The second electrode layer 140 canalso include at least one of the ohmic layer 142, the reflective layer144, the adhesive layer 146, and the second substrate 148. For example,the second electrode layer 140 may include only both the ohmic layer 142and the reflective layer 144.

In the light emitting device according to the current embodiment and amethod of manufacturing the light emitting device, a process of formingthe current blocking layer 150 is separated from a heat treating processof the ohmic layer 142 and the reflective layer 144 to form a currentblocking layer that is not affected by the heat treating process andmaterial diffusion of the reflective layer 144, thus providing a lightemitting device having a high light emitting efficiency.

Further, in the current embodiment, the current blocking layer 150 isformed, which uses a Schottky contact through a non-ohmic metal toprevent a current from flowing into the second conductive typesemiconductor layer 130 below the region of the first electrode 160.Thus, because the current blocking layer is not affected by the heattreating process for forming the ohmic layer and the diffusion of thematerial of the reflective layer, the light emitting device has a highlight emitting efficiency.

That is, according to the current embodiment, the ohmic layer 142 andthe reflective layer 144 that deform the current blocking layer 150 areseparated from the current blocking layer 150 to dispose the ohmic layer142 and the reflective layer 144 out of the region that is disposedunder the region of the first electrode 160 on the current blockinglayer 150.

The current blocking layer 150 is also formed of a metal than can form aSchottky contact with the second conductive type semiconductor layer130. For example, the current blocking layer 150 may be formed of atleast one of titanium (Ti), zirconium (Zr), chrome (Cr), gold (Au),tungsten (W), and/or an alloy including at least one of titanium (Ti),zirconium (Zr), chrome (Cr), gold (Au), and/or tungsten (W).

The current blocking layer 150 may also vertically overlap the firstelectrode 160. Further, the ohmic layer 142 is in ohmic contact with thesecond conductive type semiconductor layer 130 in the region out of thecurrent blocking layer 150. Thus, as depicted by dashed lines of FIG. 1,current flowing from the second electrode layer 140 to the firstelectrode 160 substantially does not flow through the region where thecurrent blocking layer 150 is disposed, but principally flows from theregion out of the current blocking layer 150 to the first electrode 160.

Accordingly, in the current embodiment, a current is substantially notinjected to the lower side of the region of the first electrode 160 tosuppress the generation of light from the active layer 120 under thefirst electrode 160, thus preventing heat from being generating from thedevice by the absorption of light generated under the first electrode160. Thus, in the light emitting device according to the currentembodiment, because the current blocking layer 150 having Schottkybarrier characteristics vertically overlaps the first electrode 160, acurrent flowing from the second electrode layer 140 to the firstelectrode 160 is prevented from intensively flowing to the lower side ofthe first electrode 160, and flows through the wide regions of thesecond conductive type semiconductor layer 130, the active layer 120,and the first conductive type semiconductor layer 110.

As a result, a current is prevented from intensively flowing to thelower side of the first electrode 160, and thus, the light emittingdevice can be driven at a stable operation voltage. In addition, when acurrent intensively flows to the lower side of the first electrode 160,light is principally generated from the active layer 120 at the lowerside of the first electrode 160. In this instance, the possibility thatlight generated from the lower side of the first electrode 160 isabsorbed by the first electrode 160 to reduce light intensity ordisappears in the light emitting device is high.

However, in the light emitting device according to the currentembodiment, current flows from the region of the second electrode layer140, which does not vertically overlap the first electrode 160, to thefirst electrode 160. Thus, a larger amount of light is generated fromthe region of the active layer 120, which does not vertically overlapthe first electrode 160 than from the region of the active layer 120,which vertically overlaps the first electrode 160.

The possibility that light generated from the region of the active layer120, which does not vertically overlap the first electrode 160, isabsorbed by the first electrode 160 to reduce the light intensity ordisappears in the light emitting device is low. Thus, the opticalefficiency of the light emitting device according to the currentembodiment is increased.

First Embodiment

Hereinafter, a method of manufacturing a light emitting device accordingto the first embodiment of the present invention will now be describedwith reference to FIGS. 2 to 6. In FIG. 2, an un-doped GaN layer, thefirst conductive type semiconductor layer 110, the active layer 120, andthe second conductive type semiconductor layer 130 are formed on a firstsubstrate 105. A buffer layer may also be formed between the firstsubstrate 105 and the un-doped GaN layer.

The first substrate 105 may also be formed of at least one of sapphire(Al₂O₃), Si, SiC, GaAs, ZnO, and/or MgO. Further, the buffer layer maybe formed as a multi-layer having a stacked structure such as AlInN/GaN,InxGa_(1-x)N/GaN, and Al_(x)In_(y)Ga_(1-x-y)N/In_(x)Ga_(1-x)N/GaN. Forexample, the buffer layer may be grown by injecting trimethylgallium(TMGa), trimethylindium (TMIn), trimethylaluminum (TMAl), hydrogen gas,and ammonia gas into a chamber.

The un-doped GaN layer may also be grown by injecting trimethylgallium(TMGa), hydrogen gas, and ammonia gas into the chamber. In addition, thefirst conductive type semiconductor layer 110 may be a nitridesemiconductor layer to which first conductive type semiconductor ionsare implanted, for example, and may be a semiconductor layer into whichN type impurity ions are implanted. The first conductive typesemiconductor layer 110 may also be grown by injecting trimethylgallium(TMGa), silane (SiN₄) gas including an N type impurity (e.g., Si),hydrogen gas, and ammonia gas into the chamber.

Further, the active layer 120 and the second conductive typesemiconductor layer 130 are formed on the first conductive typesemiconductor layer 110. Also, the active layer 120 may be formed in atleast one of a single quantum well structure, a multi quantum well (MQW)structure, a quantum-wire structure, and a quantum dot structure. Forexample, trimethylgallium (TMGa) gas, ammonia (NH₃) gas, nitrogen (N₂)gas, and trimethylindium (TMIn) gas may be injected to the active layer120 to form a multi quantum well structure, but the present disclosureis not limited thereto.

The active layer 120 may also be formed of at least one of InGaN/GaN,InGaN/InGaN, AlGaN/GaN, InAlGaN/GaN, GaAs/AlGaAs(InGaAs), andGaP/AlGaP(InGaP). In addition, the second conductive type semiconductorlayer 130 may be a nitride semiconductor layer to which secondconductive type semiconductor ions are implanted, for example, may be asemiconductor layer into which P type impurity ions are implanted. Thesecond conductive type semiconductor layer 130 may also be grown byinjecting trimethylgallium (TMGa), bis-ethyl-cyclopentadienyl-magnesium(EtCp₂Mg){Mg(C₂H₅C₅H₄)₂} including a P type impurity (e.g., Mg),hydrogen gas, and ammonia gas into the chamber.

Thereafter, as shown in FIG. 2, a first pattern 210 is formed in thesecond region on the second conductive type semiconductor layer 130. Inmore detail, the first pattern 210 is used to selectively form thecurrent blocking layer 150 on the second conductive type semiconductorlayer 130. The first pattern 210 may also be formed as a layer such as adielectric or a photosensitive layer.

Thereafter, the ohmic layer 142 is formed in the first region on thesecond conductive type semiconductor layer 130. In addition, the firstregion may be a portion of the upper surface of the second conductivetype semiconductor layer 130 except for the second region provided withthe first pattern 210. For example, the ohmic layer 142 may be formed bystacking a material such as a single metal, a metal alloy, or a metaloxide in multi layers to effectively inject holes. For example, theohmic layer 142 may include at least one of ITO, IZO (In—ZnO), GZO(Ga—ZnO), AZO (Al—ZnO), AGZO (Al—GaZnO), IGZO (In—GaZnO), IrOx, RuOx,RuOx/ITO, Ni/IrOx/Au, Ni/IrOx/Au/ITO, Ni, Pt, Cr, Ti, and\or Ag, but thepresent disclosure is not limited thereto.

In the current embodiment, the ohmic layer 142 is lower than the firstpattern 210, but the present disclosure is not limited thereto. Next,referring to FIG. 3, the reflective layer 144 is formed on the ohmiclayer 142. For example, the reflective layer 144 may be formed as ametal layer including Al, Ag, or APC alloy (alloy including Ag, Pd, andCu). A material such as aluminum or silver effectively reflects lightgenerated from an active layer to significantly improve extractionefficiency of a light emitting device. At this point, the reflectivelayer 144 has the same level as that of the first pattern 210, but isnot limited thereto.

Next, referring to FIG. 4, the first pattern 210 is removed to exposethe second region, and the current blocking layer 150 is formed on thesecond conductive type semiconductor layer 130 in the exposed secondregion. The current blocking layer 150 may also be formed of a non-ohmicmetal. For example, the current blocking layer 150 may be formed of atleast one of titanium (Ti), zirconium (Zr), chrome (Cr), gold (Au),and/or tungsten (W) as a metal in Schottky contact with the secondconductive type semiconductor layer 130 in the exposed second region.The current blocking layer 150 may also include various metals includinga non-ohmic metal with aluminum (Al) on the second conductive typesemiconductor layer 130.

In the light emitting device according to the current embodiment and themethod of manufacturing the light emitting device, the process offorming the current blocking layer is separated from a heat treatingprocess of the ohmic layer and the reflective layer to form a currentblocking layer that is not affected by the heat treating process andmaterial diffusion of the reflective layer, thus providing a lightemitting device having high light emitting efficiency.

Thereafter, as shown in FIG. 5, the adhesive layer 146 is formed on thereflective layer 144 and the current blocking layer 150, but the formingof the adhesive layer 146 is not always needed. That is, the reflectivelayer 144 may function as an adhesive layer, and the forming of theadhesive layer 146 may be removed.

Thereafter, the second substrate 148 is formed on the adhesive layer146. Then, when the first conductive type semiconductor layer 110 has asufficient thickness of about 50 μm or greater, the forming of thesecond substrate 148 is removed. The second substrate 148 may be formedof one of a metal, a metal alloy, and\or a conductive semiconductormaterial, which have high electrical conductivity, to efficiently injectholes to the second substrate 148. For example, the second substrate 148may be formed of copper (Cu), copper alloy (CuAlloy), Si, Mo, or SiGe. Amethod of forming the second substrate 148 may also be anelectrochemical metal deposition method or a bonding method usingeutectic metal.

Next, referring to FIG. 6, the first substrate 105 is removed to exposethe first conductive type semiconductor layer 110. In more detail, toremove the first substrate 105, a high power laser or a chemical etchingmethod may be used. In addition, the first substrate 105 may bephysically ground to remove the first substrate 105. Thereafter, theun-doped GaN layer and the buffer layer may be removed if they arepresent. The first electrode 160 is then formed on the first conductivetype semiconductor layer 110. For example, the first electrode 160 maybe formed of at least one of titanium (Ti), chrome (Cr), nickel (Ni),aluminum (Al), platinum (Pt), and\or gold (Au).

In addition, the first electrode 160 is formed on the first conductivetype semiconductor layer 110, and may have at least one portion thatvertically overlapping the current blocking layer 150. Accordingly, acurrent flowing to the first electrode 160 substantially does not flowthrough the region where the current blocking layer 150 is disposed, andflows through the region out of the current blocking layer 150.

Accordingly, in the current embodiment, a current is substantially notinjected to the lower side of the region of the first electrode 160 tosuppress the generation of light from the active layer 120 under thefirst electrode 160, thus preventing heat from being generated from thedevice by the absorption of light generated under the first electrode160.

Second Embodiment

Hereinafter, a method of manufacturing a light emitting device accordingto the second embodiment will now be described with reference to FIGS. 7to 10. The second embodiment may adopt some of the technical features ofthe first embodiment, and thus the differences between the embodimentswill be principally described.

Referring to FIG. 7, an un-doped GaN layer, the first conductive typesemiconductor layer 110, the active layer 120, and the second conductivetype semiconductor layer 130 are formed on the first substrate 105. Abuffer layer may also be formed between the first substrate 105 and theun-doped GaN layer. Thereafter, the ohmic layer 142 and the reflectivelayer 144 are formed on the second conductive type semiconductor layer130.

A second pattern 220 is then formed on the first region of thereflective layer 144. The second pattern 220 may be formed as a layersuch as a dielectric or a photosensitive layer. Thereafter, the ohmiclayer 142 and the reflective layer 144 in the second region are removedusing the second pattern 220 as a mask, so as to partially expose thesecond conductive type semiconductor layer 130. The second region mayalso vertically correspond to the region where the first electrode 160will be formed later.

Next, referring to FIG. 8, the current blocking layer 150 is formed onthe second conductive type semiconductor layer 130 exposed in the secondregion. For example, the current blocking layer 150 may be formed of atleast one of titanium (Ti), zirconium (Zr), chrome (Cr), gold (Au),and/or tungsten (W) as a metal in Schottky contact with the secondconductive type semiconductor layer 130 in the exposed second region.

In the light emitting device according to the current embodiment and themethod of manufacturing the light emitting device, the process offorming the current blocking layer is separated from a heat treatingprocess of the ohmic layer and the reflective layer to form a currentblocking layer that is not affected by the heat treating process andmaterial diffusion of the reflective layer, thus providing a lightemitting device having high light emitting efficiency.

Next, referring to FIG. 9, the second pattern 220 is removed, and theadhesive layer 146 may be formed on the reflective layer 144 and thecurrent blocking layer 150. Thereafter, the second substrate 148 isformed on the adhesive layer 146. Next, referring to FIG. 10, the firstsubstrate 105 and the un-doped GaN layer are removed to expose the firstconductive type semiconductor layer 110. The buffer layer is alsoremoved if it is present. Thereafter, the first electrode 160 is formedon the first conductive type semiconductor layer 110. The firstelectrode 160 may have at least one portion that vertically overlappingthe current blocking layer 150.

Accordingly, in the current embodiment, a current is substantially notinjected to the lower side of the region of the first electrode 160 tosuppress the generation of light from the active layer 120 under thefirst electrode 160, thus preventing heat from being generated from adevice by the absorption of light generated under the first electrode160.

In the light emitting device according to the current embodiment and themethod of manufacturing the light emitting device, the process offorming the current blocking layer is separated from a heat treatingprocess of the ohmic layer and the reflective layer to form a currentblocking layer that is not affected by the heat treating process andmaterial diffusion of the reflective layer, thus providing a lightemitting device having high light emitting efficiency.

Next, FIG. 11 is a cross-sectional view of an LED package 200 includingthe LED 100 according to an embodiment of the present invention.Referring to FIG. 11, the LED package 200 includes a body 205, a thirdelectrode layer 211 and a fourth electrode layer 212 disposed in thebody 205, the LED 100 disposed in the body 205 and electricallyconnected to the third electrode layer 211 and the fourth electrodelayer 212, and a molding member 240 surrounding the LED 100.

Further, the body 205 may be formed of a silicon material, a syntheticresin material, or a metal material. An inclined surface may also bedisposed around the LED 100. In addition, the third electrode layer 211and the fourth electrode layer 212 are electrically separated from eachother and supply a power to the LED 100. Also, the third electrode layer211 and the fourth electrode layer 212 reflect light generated in theLED 100 to improve light efficiency in the package.

In addition, the third electrode layer 211 and the fourth electrodelayer 212 release heat generated in the LED 100 to the outside. Further,the vertical type LED illustrated in FIG. 1 may be applicable as the LED100, but is not limited thereto. For example, a lateral type LED may beapplicable as the LED 100.

In addition, the LED 100 may be disposed on the body 205 or on the thirdelectrode layer 211 or the fourth electrode layer 212. The LED 100 mayalso be electrically connected to the third electrode layer 211 and/orthe fourth electrode layer 212 through a wire 230. In this embodiment,the vertical type LED 100 is explained as an example, and one wire 230may be used as an example, but is not limited thereto.

The molding member 240 also surrounds the LED 100 to protect the LED100. Also, a phosphor may be contained in the molding member 240 to varya wavelength of light emitted from the LED 100.

In addition, the LED package according to an embodiment may beapplicable to a lighting system. The lighting system may include alighting unit illustrated in FIG. 12 and a backlight unit illustrated inFIG. 13. In addition, the lighting system may include traffic lights, avehicle headlight, and a sign.

In more detail, FIG. 12 is a perspective view of a lighting unit 1100according to an embodiment of the present invention. Referring to FIG.12, the lighting unit 1100 includes a case body 1110, a light emittingmodule 1130 disposed in the case body 1110, and a connection terminal1120 disposed in the case body 1110 to receive a power from an externalpower source.

The case body 1110 may be formed of a material having an improved heatdissipation characteristic. For example, the case body 1110 may beformed of a metal material or resin material. In addition, the lightemitting module 1130 includes a substrate 1132 and at least one lightemitting device package 200 mounted on the substrate 1132.

A circuit pattern may also be printed on an insulation material to formthe substrate 1132. For example, the substrate 1132 may include aprinted circuit board (PCB), a metal core PCB, a flexible PCB, or aceramic PCB. Also, the substrate 1132 may be formed of a material thatcan effectively reflect light. A surface of the substrate 1132 may alsobe coated with a colored material, e.g., a white or silver-coloredmaterial by which light is effectively reflected.

In addition, the light emitting device package 200 may be mounted on thesubstrate 1132 and include at least one light emitting diode 100. Thelight emitting diode 100 may also include a colored light emitting diodethat emits red, green, blue, or white light, and an UV light emittingdiode that emits ultraviolet (UV) light.

Further, the light emitting module 1130 may include a plurality of lightemitting device packages 200 to obtain various colors and brightness.For example, a white LED, a red LED, and a green LED may be disposed incombination with each other to secure a high color rendering index(CRI).

The connection terminal 1120 may also be electrically connected to thelight emitting module 1130 to supply a power. As shown in FIG. 12,although the connection terminal 1120 is screw-inserted into an externalpower source in a socket manner, the present disclosure is not limitedthereto. For example, the connection terminal 1120 may have a pin shape.Thus, the connection terminal 1120 may be inserted into the externalpower source or connected to the external power source using aninterconnection.

Next, FIG. 13 is an exploded perspective view of a backlight unit 1200according to an embodiment of the present invention. As shown, thebacklight unit 1200 includes a light guide plate 1210, a light emittingmodule 1240, a reflective member 1220, and a bottom cover 1230, but isnot limited thereto. The light emitting module 1240 also provides lightto the light guide plate 1210. Further, the reflective member 1220 maybe disposed below the light guide plate 1210. The bottom cover 1230 mayalso receive the light guide plate 1210, the light emitting module 1240,and the reflective member 1220.

In addition, the light guide plate 1210 diffuses light to produce planarlight. Further, the light guide plate 1210 may be formed of atransparent material. For example, the light guide plate 1210 may beformed of one of an acrylic resin-based material such aspolymethylmethacrylate (PMMA), a polyethylene terephthalate (PET) resin,a poly carbonate (PC) resin, a cyclic olefin copolymer (COC) resin,and/or a polyethylene naphthalate (PEN) resin.

In addition, the light emitting module 1240 provides light to at leastone surface of the light guide plate 1210. Thus, the light emittingmodule 1240 may be used as a light source of a display device includingthe backlight unit. The light emitting module 1240 may also contact thelight guide plate 1210, but is not limited thereto. In particular, thelight emitting module 1240 includes a substrate 1242 and a plurality oflight emitting device packages 200 mounted on the substrate 1242. Thesubstrate 1242 may also contact the light guide plate 1210, but is notlimited thereto.

Further, the substrate 1242 may be a PCB including a circuit pattern.However, the substrate 1242 may include a metal core PCB or a flexiblePCB as well as the PCB, but is not limited thereto. Also, a lightemitting surface of each of the plurality of light emitting devicepackages 200 may be spaced a predetermined distance from the light guideplate 1210.

Further, the reflective member 1220 may be disposed below the lightguide plate 1210. The reflective member 1220 also reflects lightincident onto a bottom surface of the light guide plate 1210 to proceedin an upward direction, thereby improving brightness of the backlightunit. For example, the reflective member may be formed of one of PET,PC, and PVC, but is not limited thereto.

In addition, the bottom cover 1230 may receive the light guide plate1210, the light emitting module 1240, and the reflective member 1220.For this, the bottom cover 1230 may have a box shape with an open upperside, but is not limited thereto. The bottom cover 1230 may also beformed of a metal material or a resin material. Also, the bottom cover1230 may be manufactured using a press forming process or an extrusionmolding process.

Thus, in embodiments of the present invention, the current blockinglayer includes metal rather than a dielectric or a non-ohmic metal toblock a current. Further, the current blocking layer is not transformedinto a layer to which a current can be injected through a heat treatingprocess to form an ohmic layer.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

1. A semiconductor light emitting device, comprising: a secondconductive type semiconductor layer; an active layer over the secondconductive type semiconductor layer; a first conductive typesemiconductor layer over the active layer; a second electrode in a firstregion under the second conductive type semiconductor layer, wherein thesecond electrode includes an ohmic layer and a reflective layer; acurrent blocking layer including a metal, wherein the current blockinglayer is disposed in a trench exposing a second region of the secondconductive type semiconductor layer, and wherein the current blockinglayer partially fills the trench; a first electrode over the firstconductive type semiconductor layer, wherein the first electrode has atleast one portion that vertically overlaps the current blocking layer;and an adhesive layer fills up the trench and the adhesive layer isdisposed on the reflective layer and the current blocking layer.
 2. Thesemiconductor light emitting device of claim 1, wherein the currentblocking layer is on the second electrode in the second region exceptfor the first region under the second conductive type semiconductorlayer.
 3. The semiconductor light emitting device of claim 1, whereinthe metal of the current blocking layer includes at least one selectedfrom the group comprising titanium (Ti), zirconium (Zr), chrome (Cr),gold (Au), and/or tungsten (W).
 4. The semiconductor light emittingdevice of claim 1, wherein the metal of the current blocking layerincludes a non-ohmic metal.
 5. The semiconductor light emitting deviceof claim 1, wherein the current blocking layer includes a Schottkycontact with the second conductive type semiconductor layer.
 6. Thesemiconductor light emitting device of claim 1, wherein the metal of thecurrent blocking layer includes aluminum (Al), and a non-ohmic metal onthe second conductive type semiconductor layer.
 7. The semiconductorlight emitting device of claim 1, wherein the current blocking layerincludes a side surface contacting the ohmic layer, and an upper surfacecontacting the second conductive type semiconductor layer.
 8. Thesemiconductor light emitting device of claim 7, wherein the ohmic layerand the reflective layer are not formed in a region where the currentblocking layer under a region of the first electrode is formed.
 9. Asemiconductor light emitting device, comprising: a second conductivetype semiconductor layer; an active layer over the second conductivetype semiconductor layer; a first conductive type semiconductor layerover the active layer; a second electrode in a first region under thesecond conductive type semiconductor layer, wherein the second electrodeincludes an ohmic layer and a reflective layer; a schottky contactlayer; and a first electrode over the first conductive typesemiconductor layer, wherein the schottky contact layer comprises amaterial that is different from a material of the reflective layer. 10.The semiconductor light emitting device of claim 9, wherein the schottkycontact layer is on the second electrode layer in a second region exceptfor the first region under the second conductive type semiconductorlayer.
 11. The semiconductor light emitting device of claim 9, whereinthe first electrode has at least one portion that vertically overlapsthe schottky contact layer.
 12. The semiconductor light emitting deviceof claim 9, wherein the schottky contact layer includes a non-ohmicmetal.
 13. The semiconductor light emitting device of claim 9, whereinthe schottky contact layer contacts with the second conductive typesemiconductor layer.
 14. The semiconductor light emitting device ofclaim 9, wherein the schottky contact layer includes a side surfacecontacting the ohmic layer, and an upper surface contacting the secondconductive type semiconductor layer.
 15. The semiconductor lightemitting device of claim 9, wherein the ohmic layer and the reflectivelayer are not formed in a region where the schottky contact layer undera region of the first electrode is formed.
 16. A semiconductor lightemitting device, comprising: a second conductive type semiconductorlayer; an active layer over the second conductive type semiconductorlayer; a first conductive type semiconductor layer over the activelayer; a second electrode including a reflective layer in a first regionunder the second conductive type semiconductor layer, wherein the secondelectrode includes an ohmic layer and a reflective layer; a currentblocking layer on the second electrode layer and not overlapping thereflective layer, wherein the current blocking layer is disposed in atrench exposing a second region of the second conductive typesemiconductor layer, and wherein the current blocking layer partiallyfills the trench; a first electrode over the first conductive typesemiconductor layer; and an adhesive layer fills up the trench and theadhesive layer is disposed on the reflective layer and the currentblocking layer.
 17. The semiconductor light emitting device of claim 16,wherein the current blocking layer is in the second region except forthe first region under the second conductive type semiconductor layer.18. The semiconductor light emitting device of claim 16, wherein thefirst electrode has at least one portion that vertically overlaps thecurrent blocking layer.